feat: Add some docs!

[popey]

What would you like to be added:

Some documentation.

Why is this needed:

There's a lot of comments in the code, explaining what the various parameters do, and how they work. But there should be some docs which are more user accessible.

I think we should start with a wiki to get the information out of the script (and my head) and into the repo initially.

Perhaps a if this gets all big and complex we start a static site containing docs generated from the repo, or readthedocs. I don't have strong opinions here.

Additional context:

Some ideas for documents

• How to install quicktest, covering the deb, and from source
• How to run existing tests in quicktest
  • Interactively
  • Headless
• How to write tests
  • Gathering screenshots and text
  • Writing the test itself
• How to debug tests
• Maybe an FAQ (although I personally don't like FAQs, as they generally mean the documentation is missing something)

[popey]

• Wiki enabled

Brain dump is the next step!

[popey]

A start has been made.

Feel free to use this issue to suggest further documents which may be useful!